<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>麻将</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        .w1 {
            width: 300px;
            height: 400px;
            margin: 50px;
            display: flex;
            flex-wrap: wrap;
            align-content: center;
            border: 1px solid #000;
            justify-content: space-around;
        }
        .w1 div {
            width: 50px;
            height: 50px;
            margin: 10px;
            border-radius: 100%;
            border: 20px solid #000;
            background-color: red;
        }
    </style>
</head>

<body>
<div class="w1">
    <div></div>
    <div></div>
    <div></div>
    <div></div>
</div>
</div>
</body>

</html>